Porous passage means and method for particle analyzing systems

Claim 2

Apparatus for controlling the presentation of particles in fluid suspension to a sensing zone to facilitate particle parameter determination in a particle analysis system of a type responsive to electrical signals generated by particles passing through the sensing zone, comprising: means defining an elongate passage for transporting the particles in suspension therethrough for sensing zone presentation at a downstream end of the passage; said passage means comprising a porous wall; means for supplying particle-containing fluid to an entrance into said passage, and for supplying sheathing fluid to said porous wall outwardly relative to said passage; and means for effecting differential pressure for causing a particle-containing stream to traverse said passage from said entrance to said downstream end and for causing movement of said sheathing fluid through said porous wall into sheathing relation to said particle-containing stream.

Claim 3

Apparatus according to claim 1, wherein said sensing zone and said elongate passage defining means comprise coaxially aligned portions of a member, and an electrode located at the downstream end of said elongate passage, said electrode comprising an element of said particle analysis system.

Claim 4

Apparatus according to claim 2, wherein said electrode comprises a ring embedded in and concentric with said passage.

Claim 5

Apparatus according to claim 1, wherein said porous wall comprises a filter so that said passage means may be immersed in a reservoir containing particle-carrying electrolyte for not only supplying particle-containing fluid to said entrance, but also particle-free sheathing fluid through said porous wall.

Claim 6

Apparatus according to claim 1, wherein said means defining an elongate passage comprises an elongate member having a downstream end portion of substantially conical shape for substantially fluid tight engagement with a complementary surface of an associated member.

Claim 7

For use in apparatus for controlling the presentation of particles in fluid suspension caused to move by differential pressure through a sensing zone to facilitate particle parameter determination in a particle analysis system of a type response to electrical signals generated by particles passing through the sensing zone; means defining an elongate passage for transporting the particles in suspension therethrough for sensing zone presentation at a downstream end of the passage; said passage means comprising a porous wall about said passage and adapted for receiving particle-containing fluid through an entrance into said passage from a source communicating with said entrance, and said porous wall being adapted to be exposed to sheathing fluid on the outside of said wall so that the sheathing fluid from the outside of said wall can pass through the porous wall into said passage in response to the differential pressure which is adapted to cause a particle-containing stream derived from said source to traverse said passage from said entrance to said downstream end and through said sensing zone and also to cause movement of the sheathing fluid through the porous wall into sheathing relation to the particle-containing stream in the passage.

Claim 8

For use in apparatus for controlling the presentation of particles in fluid suspension caused to move by differential pressure through a sensing zone to facilitate particle parameter determination in a particle analysis system of a type response to electrical signals generated by particles passing through the sensing zone; means defining an elongate passage for transporting the particles in suspension therethrough for sensing zone presentation at a downstream end of the passage; said passage means comprising a porous wall about said passage and adapted for receiving particle-containing fluid through an entrance into said passage from a source communicating with said entrance, and said porous wall being adapted to be exposed to sheathing fluid on the outside of said wall so that the sheathing fluid from the outside of said wall can pass through the porous wall into said passage in response to the differential pressure which is adapted to cause a particle-containing stream derived from said source to traverse said passage from said entrance to said downstream end and through said sensing zone and also to cause movement of the sheathing fluid through the porous wall into sheathing relation to the particle-containing stream in the passage.

Claim 9

Means according to claim 6, wherein the sensing zone and said elongate passage defining means comprise coaxially aligned portions of a member, and an electrode located at the downstream end of said elongate passage and comprising an element of the particle analysis system.

Claim 10

Means according to claim 6, wherein said electrode comprises a ring embedded in said member coaxially aligned with said passage.

Claim 11

Means according to claim 6, wherein said porous wall comprises a filter so that said means can be immersed in particle-containing electrolyte for providing both the particle-containing fluid in the passage and particle-free sheathing fluid through said wall into said passage.

Claim 12

Means according to claim 6, comprising a member having said porous wall and provided with a substantially conical surface adapted to interfit in substantial fluid tight connection with a complementary surface of an associated member.

Claim 15

A method according to claim 11, which comprises causing the sheathed particle-containing stream to travel uninterruptedly from said downstream end of said passage into and through said sensing zone past an electrode which is part of said particle analysis system.

Claim 16

A method according to claim 11, which comprises filtering the sheathing fluid through said wall so that the sheathing fluid enters said passage through said wall in particle-free condition.

Claim 17

A method according to claim 11, wherein said passage and porous wall are part of a member, and immersing said member in a reservoir providing a common supply of the particle-containing fluid and sheathing fluid and filtering particles from the sheathing fluid on passing through said porous wall into said passage.